DataXu said it raised $27 million in a round of financing led by Thomvest Ventures and joined by existing investors Atlas Venture, Flybridge Capital Partners and Menlo Ventures. Thomvest Managing Director Stefan Clulow joins DataXu’s board.

Dataxu, a Boston-based operator of a real-time bidding platform for online display advertisers, has raised $11 million in Series B funding. Menlo Ventures led the round, and was joined by return backers Atlas Venture and Flybridge Capital Partners. The company previously raised just over $6 million.

Dataxu, an online advertising startup run by former Enpocket and Nokia Interactive chief Michael Baker, has raised just over $6 million in first-round funding, according to a regulatory filing. Backers include Atlas Venture and Flybridge Capital Partners, with Jeff Fagnan (Atlas) and Jeff Bussgang (Flybridge and prolific peHUB contributor) joining the company’s board of directors.

Dataxu (pronounced data-zoo) was founded in 2007 by MIT professor Ed Crawley. Its first CEO was Bruce Journey, who had spent the prior decade as publisher of the MIT Technology Review. It’s not exactly clear when he turned the reins over to Baker, as their LinkedIn profiles have conflicting dates (Journey claims to have been CEO though last month, while Baker’s says he took over in September 2008). I tried leaving a voicemail for Baker, but was instead (repeatedly) directed to Journey’s recording.